Calculate your estimated due date (EDD) based on your last menstrual period or conception date. See your current pregnancy week, trimester, and all key milestone dates.
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LMP (Last Menstrual Period) is the most common method used by doctors.
Default is 28 days. Adjust if your cycle is longer or shorter.
See current week, trimester, and all key dates.
Naegele's Rule (standard obstetric method):
For cycles other than 28 days, the due date is adjusted by the difference from 28. A 30-day cycle shifts the due date 2 days later. Conception is estimated at LMP + (cycle length − 14) days.
The EDD is an estimate — only about 5% of babies are born on the exact due date. Full term is 37–42 weeks. Your OB will confirm dates via ultrasound, which is more accurate.
Last Menstrual Period — the first day of your last period before conception. Doctors use this as the starting point for pregnancy dating even though conception happens ~14 days later.
Naegele's Rule: add 280 days (40 weeks) to the first day of your LMP. This assumes a 28-day cycle with ovulation on day 14.
1st trimester: weeks 1–12. 2nd trimester: weeks 13–26. 3rd trimester: weeks 27–40. The 2nd trimester is typically the most comfortable.
Only about 5% of babies are born on their exact due date. 80% arrive within 2 weeks before or after. The due date is an estimate based on an average 280-day pregnancy. Ultrasound dating is more accurate than LMP calculation.